US3701939A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Reverse voltage circuit for thyristors
Assignee: Danfoss AS
•
Filing: 1970-12-28
•
Granted: 1972-10-31
•
Expires: 1990-12-28
Abstract
Abstract The invention relates to a reverse voltage circuit for thyristors which has particular application to an inverter circuit. The basic circuit includes a thyristor, a first diode, and a transformer having the primary winding thereof in series relation to the diode. The first diode and the transformer primary winding are in parallel relation to the thyristor with the diode being antiparallel relative to the thyristor. The transformer secondary winding and a second diode are in series and a D.C. voltage source biases the second diode in a counter direction relative to the secondary winding. With this circuit higher reverse voltages are obtained having relatively lengthy durations to effect switching off of a thyristor in a satisfactory manner.
Inventors
- 👤 Tom Kastrup Petersen
- 👤 Neils Juul Henriksen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 17:40
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/51; H03K17/56; H03K17/72; H02; H02M; H02M1/00; H02M1/06
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
207 words
A reverse voltage circuit for a thyristor comprising: a thyristor; a transformer having a primary winding and a secondary winding; a first conductor path connected in parallel with said thyristor, said first path including said primary winding in series with a first diode poled in the reverse direction relative to said thyristor; a second conductor path connected in parallel with said thyristor, said second path including commutator means and switch means which is closed under the control of said commutator means when a reverse voltage is to be applied across said thyristor, closure of said switch means causing a current to flow in said first path in the forward conducting direction of said first diode; a second diode and a capacitor connected in series with said secondary winding; and charging means for charging said capacitor in a sense to apply a reverse voltage across said second diode; closure of said switch means causing a current to flow in said primary winding to induce a voltage in said secondary winding sufficient to overcome the reverse voltage across said second diode whereby current flows In said secondary winding and a reverse voltage substantially in excess of the forward voltage drop of the first diode is applied across said thyristor.
Claim 2
Dependent Claim
207 words
A reverse voltage circuit for a thyristor comprising: a thyristor; a transformer having a primary winding and a secondary winding; a first conductor path connected in parallel with said thyristor, said first path including said primary winding in series with a first diode poled in the reverse direction relative to said thyristor; a second conductor path connected in parallel with said thyristor, said second path including commutator means and switch means which is closed under the control of said commutator means when a reverse voltage is to be applied across said thyristor, closure of said switch means causing a current to flow in said first path in the forward conducting direction of said first diode; a second diode and a capacitor connected in series with said secondary winding; and charging means for charging said capacitor in a sense to apply a reverse voltage across said second diode; closure of said switch means causing a current to flow in said primary winding to induce a voltage in said secondary winding sufficient to overcome the reverse voltage across said second diode whereby current flows In said secondary winding and a reverse voltage substantially in excess of the forward voltage drop of the first diode is applied across said thyristor.
Claim 3
Dependent Claim
18 words
A reverse voltage circuit according to claim 1 wherein said charging means is a constant voltage D.C. supply.
Claim 4
Dependent Claim
226 words
An inverter comprising at least one thyristor phase branch with first and second thyristors in series; first and second transformers each having primary and secondary windings, said primary windings being in series with each other and with said thyristors, said primary windings being between said thyristors, and the common junction of said primary windings forming a phase voltage tapping; a first diode in parallel with said primary windings and said first thyristor; a second diode in parallel with said primary windings and said second thyristor, said diodes being in anti-parallel relation respectively to said thyristors; a path connected in parallel with said branch, said path including commutator means and switch means which is closed under the control of said commutator means when a reverse voltage is to be applied across said thyristors; a third diode and a capacitor connected in series with said secondary windings; and charging means for charging said capacitor in a sense to apply a reverse voltage across said third diode; closure of said switch means causing a current to flow in said primary windings to induce a voltage in said secondary windings sufficient to overcome the reverse voltage across the third diode whereby current flows in said secondary windings and a reverse voltage substantially in excess of the forward voltage drops of the first and second diodes is applied across said thyristors.
Claim 5
Dependent Claim
226 words
An inverter comprising at least one thyristor phase branch with first and second thyristors in series; first and second transformers each having primary and secondary windings, said primary windings being in series with each other and with said thyristors, said primary windings being between said thyristors, and the common junction of said primary windings forming a phase voltage tapping; a first diode in parallel with said primary windings and said first thyristor; a second diode in parallel with said primary windings and said second thyristor, said diodes being in anti-parallel relation respectively to said thyristors; a path connected in parallel with said branch, said path including commutator means and switch means which is closed under the control of said commutator means when a reverse voltage is to be applied across said thyristors; a third diode and a capacitor connected in series with said secondary windings; and charging means for charging said capacitor in a sense to apply a reverse voltage across said third diode; closure of said switch means causing a current to flow in said primary windings to induce a voltage in said secondary windings sufficient to overcome the reverse voltage across the third diode whereby current flows in said secondary windings and a reverse voltage substantially in excess of the forward voltage drops of the first and second diodes is applied across said thyristors.
References Cited (Backward Citations)
US3308371A
Cited
US3349315A
Cited
US3405346A
Cited
GB1174086A
Cited
US3641364A
Cited
US3629673A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-10-31 | 1976-05-01 | 1976-10-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-31 | 1980-05-01 | 1980-10-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-31 | 1984-05-01 | 1984-10-31 | $7700.00 | Window Closed / Lapsed |